MADISON - A group of Republicans is seeking to change the state constitution to prevent courts from keeping abortion legal, but Democrats contend the measure could outlaw some forms of birth control.

The tactic has split abortion opponents, with some saying the proposed constitutional amendment would hurt their long-term goal of outlawing abortion. Because of that internal dispute, the proposal faces no chance of getting through the Republican-controlled Legislature this spring.

Supporters say what they call a personhood amendment is meant to ensure abortion is illegal if the U.S. Supreme Court overturns rulings that have guaranteed a right to abortion.

The state constitution says all people are born equally free and independent. The proposed amendment would drop the word “born” and say the right to life applies to all humans at any stage of development, including before they are born.

The proposed amendment would allow the Legislature to specify what protections could be afforded to the unborn.

To take effect, the measure would have to pass the Legislature this spring; pass the Legislature again in 2021 or 2022; and win approval from voters in a statewide referendum.

GOP state Sen. André Jacque of DePere said he was trying to advance the measure to make sure a Wisconsin law criminalizing abortion automatically takes effect if the U.S. Supreme Court overturns Roe v. Wade and other abortion rulings.

The supreme courts of Iowa and Kansas in recent years determined their states’ constitutions guaranteed a right to abortion. Jacque said he wanted to make sure the Wisconsin Supreme Court didn’t reach a similar conclusion.

“The potential exists for a future Wisconsin Supreme Court to similarly find a right to abortion in the Wisconsin Constitution — and they would assuredly have an even easier time doing so” because the state constitution gives rights to those who are "born,” Jacque testified Thursday before the Assembly Health Committee.

Wisconsin’s Supreme Court has a 5-2 conservative majority, but Jacque said that could change in the coming years.

Opponents said changing the constitution could result in courts ruling life begins with the fertilization of an egg and make IUDs or other forms of birth control illegal.

”That idea scares us so much because as soon as you recognize the rights of that fertilized egg, which most of us don’t know is inside of us, then you put us up for criminal penalty if we smoke a cigarette, if we take birth control, if we go rock climbing, if we take chemotherapy because we have cancer,” said Sara Finger, executive director of the Wisconsin Alliance for Women’s Health.

Supporters of the measure disputed that idea, saying the proposed amendment was meant to leave it to lawmakers to decide what conduct would be illegal.

James Bopp Jr., a nationally known attorney who has done work for Wisconsin Right to Life, testified Thursday that there was no way to know how courts might rule if the amendment were adopted — and they might rule in a way that makes it harder to ban abortion.

"This is too risky," he told lawmakers.

The measure got a hearing just as the legislative session is winding down.

Assembly Speaker Robin Vos, R-Rochester, said the measure would not get to the floor before his house wraps up its session for the year next week.

The Wisconsin statute outlawing abortion has been sidelined for decades because of court rulings, but abortion opponents argue it will be immediately reinstated if those court rulings are overturned. The proposed constitutional amendment is intended to make sure that happens.